Solvent-Free Condensation of Pyrrole and Pentafluorobenzaldehyde:  A Novel Synthetic Pathway to Corrole and Oligopyrromethenes

Abstract

The solvent-free condensation of pyrrole and pentafluorobenzaldehyde (and to a lesser extent other electron-poor aldehydes as well) leads to a variety of products, of which three have been isolated and fully characterized. The two main products (11% each) are an open-chain pentapyrrole and corrole, a tetrapyrrolic macrocycle.

Cellular uptake and anticancer activity of carboxylated gallium corroles

“…Corroles have received a great deal of attention in recent years (10)(11)(12)(13), owing to dramatic advances in methods for their preparation (14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31). Of interest here is a gallium(III) complex, 1 [Ga(tpfc)] (32)(33)(34)(35), where tpfc represents the trianion of 5,10,15-tris(pentafluorophenyl)corrole [H 3 (tpfc)].…”

A Perspective of One‐Pot Pyrrole–Aldehyde Condensations as Versatile Self‐Assembly Processes

“…[83,84] As early as 1996, Rose et al [85] reported the isolation of meso-tris(4-tert-butyl-2,6-dinitrophenyl)corrole as a minor by-product of a classical porphyrin synthesis, but the significance of this finding went almost unnoticed. The situation changed in 1999 with reports by Gross et al [86,87] and Paolesse et al [88,89] of one-pot corrole syntheses-initially still serendipitous-involving pyrrole-aldehyde condensations.…”

“…[89] In contrast, the research group of Gross reported a fast, [86,87] essentially solvent-free, catalyst-free condensation of pyrrole with aldehydes in an open vessel in the presence of basic alumina as a solid support, followed by oxidation with DDQ in CH 2 Cl 2 to yield the correponding corroles. Gross and co-workers reported solvent-free syntheses of meso-tris(pentafluorophenyl)corrole ((TPFC)H 3 ), meso-tris(2,6-dichlorophenyl)corrole, and meso-tris(heptafluoropropyl)corrole [90] (Scheme 13), mentioning that their procedure worked best for relatively electron-deficient aldehydes.…”

“…Gross and co-workers reported solvent-free syntheses of meso-tris(pentafluorophenyl)corrole ((TPFC)H 3 ), meso-tris(2,6-dichlorophenyl)corrole, and meso-tris(heptafluoropropyl)corrole [90] (Scheme 13), mentioning that their procedure worked best for relatively electron-deficient aldehydes. [87] Our own contribution to one-pot pyrrole-aldehyde condensation reactions consisted of an investigation into the scope of the solvent-free corrole synthesis. In our hands, the solvent-free corrole synthesis turned out to be more general than originally claimed, [85,86] as both electron-rich and electron-deficient aromatic aldehydes yielded the corresponding meso-triaryl corroles (Scheme 14).…”

Recent developments in out-of-plane metallocorrole chemistry across the periodic table

“…Subsequent study was hampered by synthetic inaccessibility of corroles until 1999, when two new routes to the preparation of free base corrole were published by Paolesse 11 and Gross. 12,13 Over the next decade, a wealth of synthetic methodologies and variants were developed for synthesis of corroles, 14 with mesosubstituents, [15][16][17][18][19][20][21] various beta-substituents, [22][23][24][25][26] and eventually including both charged 27,28 and chiral 29 free-base corroles. The development of these organic syntheses is beyond the scope of this review, but the range of properties imparted by these synthetic options has greatly broadened the scope of applications of corroles.…”